The present invention is directed to a device for releasably connecting a head part to a handle part of a dental handpiece.
In the dental practice, the most wide spread type of connection for releasably connecting a head part to a handle part of a dental handpiece is a screwed or threaded connection. However, the threaded connection has a disadvantage of the diameter of the handpiece being increased at the location of the connection. Moreover, such a connection does not allow for a sufficiently quick separation of the connection or coupling and a subsequent recoupling or reconnection of the handpiece parts particularly because of the fine pitched threads which are usually utilized in the threaded connection.
It is further known to connect the head part to the handle part by means of a bayonet joint or catch. However, the twisting of the two handpiece parts with respect to one another which is required by such a joint is not desirable for a dental hand with an angled piece and particularly for a dental handpiece which has cooling agent lines incorporated within the parts or pieces.
To couple dental handpiece parts together, a device is known which contains a radially projecting, spring loaded pin or stop bolt on one of the handpiece parts which engages in a snap ring groove on the other handpiece part when the two handpiece parts are coupled together. To enable uncoupling, an actuation button is provided at another location of the handpiece part and influences the resiliently arranged stop bolt or spring loaded pin and lifts the pin or bolt out of the snap ring groove when the button is actuated. A major disadvantage with such a device is that the actuation button projects beyond the surface of the handpiece.